Every other Friday on Morning Edition, Outside/In host Sam Evans-Brown tackles a question from a listener.
Peter from Londonderry asks: Are there certain audio frequencies that birds can hear but humans can’t, in a similar way that dog whistles work?
Humans (especially brand new baby humans that haven’t damaged their delicate hair cells) can hear up to 20,000 hertz. Dogs can hear up to 35,000 or even 65,000 hertz.
In hunting around for studies on bird hearing, I was directed to one promisingly titled High Frequency Hearing in a Hummingbird which claimed to have found “the highest in any bird vocalization known to date” made by the Ecuadorian Hillstar Hummingbird which was around… 13,000 hertz.
The piece notes, “The frequency content of this song is also far beyond the hearing range in most birds (2 to 8 kHz).”
So the answer, in so far as we know currently, is “No.” Next question?
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Just kidding, that’s not all! Now watch me pivot seamlessly to other nifty bird hearing facts.
Birds Hear in Slow Motion
Smaller creatures generally, including birds, actually perceive time differently than we do. A paper from 2013 detailed an experiment where researchers measured the neural response of animals to a blinking strobe light. Researchers sped up the blinking, faster and faster, until animals started to perceive it as not blinking anymore.
The finding was that the smaller the creature, the faster they were able to distinguish the blinking. A later study focused on birds specifically, and found a similar pattern: the smaller the bird, the faster it perceives the world.
And with birds, this means they’re able to distinguish between notes in bird song that go by too fast for the human ear.
Owls Have Astonishing Ears
The unchallenged champions in avian audition are owls, particularly barn owls.
Their ears are asymmetrical, which apparently helps them to distinguish the elevation of their prey, so they can swoop down on them in the middle of the night.
And Marcela Fernandez-Peters, a researcher at UMass Amherst, says that when you look inside the hearing organs and brains of owls, “they do have a lot of real estate dedicated to these high frequencies.” Which is to say, they might not hear super high pitched sounds, but they’re *very* good at hearing the frequencies they do hear.
Experiments have shown that barn owls hunt almost entirely with their ears. One “classic” experiment featured mice walking on a quiet surface through a dark room, but with a noisy piece of paper tied behind them, which led the owls to attack the paper.
Birds Don’t Go Deaf
And lastly, the niftiest thing about bird ears — and the thing that we’re most interested in studying because it would be useful for us to know how they do it — birds don’t get hearing loss. The little delicate hair cells that we use to detect sound? In humans, once you damage them, they’re gone forever. Birds grow them back.
There are researchers out there trying to figure out how to harness that to our advantage, which — and I say this as human, not just the son of an audiologist — is pretty cool.
Sam Evans-Brown, is host ofNHPR’s Outside/In which you can subscribe to where-ever you get your podcasts. If you’d like to submit a question you can record it as a voice memo on your smartphone and send it to oustidein@nhpr.org, OR call the hotline, 1-844-GO-OTTER, OR submit it here.
